Effect of pre- and postmating nutritional manipulation on plasma progesterone,blastocyst development,and the oviductal environment during early pregnancy in gilts   总被引：5，自引：0，他引：5  

Novak S  Almeida FR  Cosgrove JR  Dixon WT  Foxcroft GR 《Journal of animal science》2003,81(3):772-783

Two experiments were conducted to determine mechanisms mediating effects of nutritional manipulation before and after mating on embryonic survival in pigs. Experiment 1 studied the mechanisms by which continued high feeding levels after mating result in differences in plasma progesterone during early pregnancy. Gilts fed 2.0 times maintenance energy requirements either remained on this high level or feed was reduced to 1.5 times maintenance immediately after mating. Ovarian, oviductal, and jugular vein progesterone concentrations were determined 72 h after onset of estrus, and samples taken every 4 h were used to determine LH and progesterone during the periestrous period. Treatment did not affect peripheral progesterone concentrations, the timing or rate of rise of progesterone, or progesterone in ovarian, oviductal, or jugular veins at the time of surgery. Time after the LH peak was highly correlated (P = 0.0001) with jugular progesterone concentrations, but not with those in oviductal and ovarian veins, suggesting that responses in the reproductive tract mediated by peripheral progesterone concentrations will be temporally different to effects within tissues supplied by the ovarian and oviductal vasculature. Experiment 2 studied mechanisms mediating nutritional manipulation in the preovulatory period on postovulatory reproductive function, using feed restriction during the first (RH) or second (HR) week of the estrous cycle. Surgeries were performed 12 to 20 h after ovulation, and fertilized oocytes were cultured for 144 h in vitro. Ovulation rate was not affected by previous nutritional regimen. Fertilization rate was higher (P = 0.056) in RH vs HR gilts, but development of cultured oocytes was not affected by treatment. There were no treatment differences in peripheral or oviductal plasma progesterone, estradiol, or insulin-like growth factor-I (IGF-I) at surgery, or in porcine oviductal secretory protein abundance and IGF-I concentrations in oviduct flushings, but treatment affected total protein concentration (P = 0.002). These results indicate that either previous nutritional treatment does not affect the early developmental competence of fertilized oocytes in vitro or differences in developmental competence of oocytes are not expressed up to the early blastocyst stage. However, the lack of an effect of previous nutrition on steroids in the local oviductal circulation may also be related to the lack of effects on oviductal function and embryonic development.  相似文献   

Association of herd productivity and bulk-tank somatic cell counts in US dairy herds in 1996     

Ott SL  Novak PR 《Journal of the American Veterinary Medical Association》2001,218(8):1325-1330

OBJECTIVE: To assess the association of bulk-tank somatic cell counts (BTSCC) and the value of herd productivity (milk produced, calves born, and net costs for cow replacements) in US dairy herds in 1996. DESIGN: Randomized stratified national survey of dairy producers. SAMPLE POPULATION: Records from 1,219 dairy herds in the top 20 dairy states. PROCEDURE: Responses for 1,178 herds had complete information for economic analysis. Per-cow value of production was determined for each herd. Data for herds with high (> or = 400,000 cells/ml) and medium (200,000 to 399,999 cells/ml) BTSCC were compared with values for herds with low BTSCC (< 200,000 cells/ml), using a multivariable regression model. RESULTS: In 1996, milk was priced at $0.287/kg ($13/cwt). Herds with low BTSCC annually generated $103.90/cow more in herd productivity than herds with medium BTSCC and $292.39/cow more than herds with high BTSCC. CONCLUSIONS AND CLINICAL RELEVANCE: Increased BTSCC (> 200,000 cells/ml) were associated with a reduced value of productivity per cow. Thus, dairy producers have a financial incentive to seek out and implement cost-effective management practices that will enable them to decrease their BTSCC to < 200,000 cells/ml and maximize herd productivity.  相似文献   

微量矿物质营养调控对生产高品质禽肉影响的研究     

Curtis Novak  Catalina Troche  王强 《中国家禽》2007,29(15):31-33

长期以来家禽养殖者们都是采用一些预防性措施来确保高产、无病害禽产品进入市场.传统意义上,这些预防性措施包括:良好的饲养管理程序、免疫接种程序、适宜的抗菌素添加剂使用和生物安全.……  相似文献   

Untersuchungen über Produktion und Konsum von Honigtau in Hecken Oberfrankens     

Dipl. Biol. H. Novak 《Journal of pest science》1992,65(3):41-48

Zusammenfassung Im Rahmen einer einjährigen Arbeit wurde die Produktion von Honigtau in oberfränkischen Hecken und dessen Nutzung durch die Arthropodenfauna untersucht. Dazu wurde das Artenpektrum und die Phänologie der phloemsaugenden Insekten mit Hilfe der Klopfprobemethode über die gesamte Vegetationsperiode hinweg erfaßt.Von den 25 an den heckentypischen Gehölzarten festgestellten Phloemsaugern traten die Psylliden an Weißdorn und die Aphididen an Schlehe in besonders großen Individuenzahlen auf. Sie stellten im Untersuchungszeitraum die ergiebigsten Honigtauproduzenten in den bearbeiteten Hecken.Die Honigtauabgabe erreichte an den meisten Heckengehölzen ihr Maximum im Frühjahr, mit einem Abklingen in den Sommermonaten und einem erneuten kleineren Anstieg im Herbst. Demgegenüber dauerte die Blattlausentwicklung an der Schlehe und der Eiche den Sommer über an und ermöglichte so ein kontinuierliches Honigtauangebot für nahrungssuchende Insekten über die ganze Vegetationsperiode.An der Schlehe konnten insgesamt 139 Insekternarten als Honigtau-Besucher festgestellt werden. Die Syrphiden waren dabei mit 16 Arten am zahlreichsten vertreten, wobeiEpisyrphus balteatus (Deg.) die mit Abstand häufigste Honigtau-Besucherin stellte.

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Studies on production and consumption of honeydew in hedges of upper frankonia

In a one-year study, the production of honeydew in hedges of Upper Frankonia and its utilization by food-searching insects were investigated. The phloemfeeding fauna and its seasonal development on hedgeshrubs were assessed by means of the beating method.Out of the 25 sap-sucking species recorded on the shrubs typical for hedges, the Psyllidae on hawthorn (Crataegus spec.) and the Aphididae on blackthorn (Prunus spinosa) were most abundant during the period of investigation producing considerable amounts of honeydew.On most hedgeplants honeydew production reached a maximum in spring with a sharp decline in summer and a second but smaller peak in autumn. In contrast, the development of the aphids on blackthorn and oak persisted throughout the summer and therefore there was a continous honeydew supply for foodsearching insect species in the hedges during the season.On blackthorn a total of 139 insect species were recorded taking up honeydew from the plant's surface. In species number as well as in individual number the syrphids were the most frequent honeydew visitors. EspeciallyEpisyrphus balteatus (Deg.) was observed to feed in great numbers on the excretions of aphids.

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Mit 3 Abbildungen und 5 Tabellen  相似文献   

Do the size and landscape context of forest openings influence the abundance and breeding success of shrubland songbirds in southern New England?     

Robert A. Askins  Benjamin Zuckerberg  Leah Novak   《Forest Ecology and Management》2007,250(3):137-147

Early successional birds have declined in the northeastern United States due to the regeneration of forest on abandoned farm fields and the suppression of natural disturbances that once provided appropriate habitat. These species have become increasingly dependent on early successional habitats generated by such activities as timber harvesting. Recent approaches of timber harvesting, which range from single-tree harvesting to clearcutting, create forest openings of different sizes and configurations embedded in landscapes with different land use patterns. To assess the importance of forest openings created by timber harvesting for shrubland birds, we surveyed birds on 50 m radius plots in 34 harvest sites (0.5–21 ha). We collected data on multi-scaled habitat variables ranging from plot-level vegetation characteristics to land use patterns within 1 km of each study site. We also monitored mating and nesting success of Blue-winged Warblers (Vermivora pinus) in 10 forest openings.

The abundance of most shrubland species was influenced by plot-level habitat variables, such as tree density and vegetation height, rather than shrubland area or the composition of land uses in the surrounding landscape. Only Eastern Towhees (Pipilo erythrophthalmus) were more frequent in survey plots in larger forest openings. In contrast, neither abundance nor reproductive activity of Blue-winged Warblers was correlated with the size of the forest opening. Their abundance was negatively related to vegetation height, however. Only 54% of the territorial male Blue-winged Warblers in forest openings were mated. We documented relatively low nest success rates of 21.1% during the egg laying and incubation nest stages, but increased success rates during the later stages of nesting.

Our results indicate that even small forest openings with low vegetation provide habitat for Blue-winged Warblers and other shrubland birds. The overall reproductive rate of territorial male Blue-winged Warblers in forests openings was low during the 2 years of the study, however. Further studies are needed to assess the long-term value of this type of habitat for sustaining shrubland bird populations.  相似文献   

Toward pollen sterility in German chamomile (Matricaria chamomilla)–Conventional breeding approaches of cytoplasmic/genic male sterility and chemical emasculation     

Bettina Faehnrich  Julia Huber  Sarah Wagner  Chlodwig Franz  Beate Fraust  Maria Wehrle  Joana Ruzicka  Johannes Novak  Lars-Gernot Otto 《Plant Breeding》2020,139(6):1299-1309

Pollen sterility (PS) in mother lines is crucial for hybrid crossings in plant breeding. 21 di- (2x) and tetraploid (4x) accessions of the hermaphroditic chamomile were screened for spontaneous, thermic or gametocide induced PS. Two crossing trials with the diploid accessions 'Bona' (BON) and 'Hungary 2' (HUN2) should specify maternally inherited cytoplasmic male sterility (CMS). Progeny thereof showed increased PS. BON as mother (BH) entailed means of 30 and 22% PS, versus 8% and 20% after reciprocal crossings. Backcrosses of BH with HUN2 in paternal and maternal direction revealed increasing mean PS (24% and 32%), without verification of CMS. A split plot design of 100 individuals treated with four chemical gametocides analyzed PS, seed set, germination rate and whole plant damage. Tri-iodobenzoic acid caused the highest PS (43%). Progeny of two plants (2x, 4x) with degenerated anthers without pollen, showed 100% PS either in tetraploid F₁ and F₂ (4% and 11%) or in diploid F₂ and F₃ (26% and 23%). High temperature (30/28°C day/night) decreased the male fertility to some extent.  相似文献   

Modelling soil temperature in forest clearcuts using climate station data     

R.J. Stathers  T.A. Black  M.D. Novak 《Agricultural and Forest Meteorology》1985,36(2):153-164

A physically based numerical model was developed to estimate the time courses of soil temperature in forest clearcuts from measured solar irradiance, air temperature and wind speed. The model is based upon a finite difference solution of the one-dimensional soil heat flow equation with a surface boundary condition determined from aerodynamic heat transfer and energy balance theory.Modelled soil temperatures were compared with data from two other studies reported in the literature and with temperatures measured in a forest clearcut during 6 and 16 day periods in the summer. The model calculated surface and subsurface soil temperatures accurately over these long intervals. Modelled soil temperatures were relatively insensitive to air temperature, soil thermal properties and the lower boundary soil temperature but quite sensitive to solar irradiance, wind speed and surface roughness.  相似文献   

Micromorphology and topography of tarsal joint capsule's vascular elements in cats and dogs     

Yevheniya Nechiporuk  Vitaliy Novak  Antonina Melnychenko  Olga Bevz  Volodymyr Dudka 《Anatomia, histologia, embryologia》2020,49(6):830-835

Both cats and dogs belong to animals with the same type of limb support but have different nature of movement. Despite belonging to digitigrade animals, cats and dogs have a different nature of motion. While moving, the medial joint surface in cats and lateral surface in dogs carry the larger pressure. The aim of the study was to compare the similar surfaces of the cat's and dog's tarsal joint capsule and to detect differences in its histostructure and vascularisation. For the study, we used the capsule of the tarsal joint of five cats and five dogs dissected with accordance to anatomical surfaces. Sections of the capsule joint were stained with haematoxylin–eosin. The sections were examined with a microscope at magnification ×250 and ×400. The statistical analysis of the results was done using Student's t test. During the research, a difference in histostructure and vascularisation of tarsal joint capsule in cats and dogs on respective surfaces were found. The medial surface of the tarsal joint capsule was the most saturated with hemomicrocirculatory bed structures in cats, whereas this was the lateral surface in dogs. The most active metabolic processes also take place in these areas of the joint capsule, which is important to know when prescribing therapeutic procedures and determining an optimal surgical access.  相似文献   

Effect of supplementation with an electrolyte containing a Bacillus-based direct-fed microbial on immune development in dairy calves     

Novak KN  Davis E  Wehnes CA  Shields DR  Coalson JA  Smith AH  Rehberger TG 《Research in veterinary science》2012,92(3):427-434

Immune characteristics in 65 calves were evaluated in response to a Bacillus-based direct-fed microbial (DFM) provided in electrolyte scour treatment. Blood samples were analyzed for cell surface markers and α(1)-acid glycoprotein (AGP) concentration. AGP increased in scouring calves given electrolyte containing Bacillus at day 7 post-placement compared to scouring calves administered electrolyte alone and non-scouring calves, enhancing the inflammatory response for pathogen clearance. The Bacillus promotes T cell subsets including greater proportions of activated, mature cells (CD8(-)CD25(+), CD8(-)CD45RO(+), CD8(-)TCR1(+)) in calves given electrolyte containing Bacillus than scouring calves administered electrolyte alone and non-scouring calves. Also, the Bacillus may be alleviating inflammation at day 3 post-placement as the proportion of monocytes and granulocytes lacking L-selectin (CD172a(+)CD62L(-)) was greater in scouring calves given electrolyte compared to the other groups. Electrolyte containing Bacillus administered at the onset of scours influences components of innate and adaptive immune development during and following the scouring event.  相似文献   

Removal of aldrin, heptachlor epoxide, and endrin from potatoes during processing     

J M Solar  J A Liuzzo  A F Novak 《Journal of agricultural and food chemistry》1971,19(5):1008-1010

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